With machines having a rotor which orbits within a housing, it is necessary for the rotors movement to be adequately controlled during its orbiting motion, for the rotor can be mounted on a crank or the main shaft of the engine, and as there are vanes or the like dividing the space between the rotor and the stationary housing in order to form working chambers, these vanes must be maintained in relationship with any porting arrangements so that the ports, vanes and rotor form the working chambers having the correct timed relationship.
Thus for this to occur it is necessary that the rotor be adequately controlled, and one way of achieving this is to have a second crank shaft mounted in the housing and having the rotor also rotatable on this crank, but it is also essential with this that the two cranks be precisely connected to rotate in unison for if not the situation could occur that at the top dead-centre positions the cranks or one crank could tend to rotate in the opposite direction.
Australian Pat. No. 474,336 discloses an orbital machine when the rotor is controlled by a pair of crank shaft geared together, and it is an object of this invention to provide a means which will adequately restrain and control the movement of the rotor in its orbital motion and which means is simple and economical to produce and incorporate in the rotary machine.